1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device in which a chemical solution treatment is performed for a base on which conductors electrically connected to each other via a p-n junction are exposed.
2. Description of the Related Art
Holes and electrons are produced when light irradiates the p-n junction of a semiconductor device. This production of the holes and electrons during the device manufacturing currently poses a problem. The problem caused by irradiation of light on the p-n junction during the manufacturing of a semiconductor device will be described with reference to FIGS. 8A and 8B. FIGS. 8A and 8B are process sectional views showing a damascene process in the manufacturing process of the semiconductor device.
Referring to FIG. 8A, reference numeral 11 denotes an Si substrate; 12, n+-type well; 13, p+-type well; 14, insulating film; 15, barrier metal; 16a and 16b, metal wirings; and 81, slurry. The wiring 16a is connected to the p+-type well 13. The wiring 16b is connected to the n+-type well 12. The wirings 16a and 16b are exposed on the upper surface and patterned to be spaced apart from each other, and the barrier metal 15 is left on the device surface in the state shown in FIG. 8A. In this state, the p+-type well 13 and n+-type well 12 are electrically connected via the barrier metal 15. Even when light irradiates the device, the produced holes and electrons are consumed in the device.
When CMP progresses, the barrier metal 15 is removed from the device surface as shown in FIG. 8B. When light irradiates the device surface in the state shown in FIG. 8B, positive ions are segregated on the surface of the wiring 16b connected to the n+-type well 12. On the other hand, the metal dissolves on the surface of the wiring 16a connected to the p+-type well 13. This results in a so-called light corrosion to deform and transelement the metal. Thus, sometimes the subsequent process cannot be performed, and the device characteristic itself is damaged.
The CMP is exemplified in this description. However, the dissolution/ion segregation reaction may occur with the same mechanism as in the above description in a solution treatment process for a device having the same structure as in FIG. 8B. For example, this problem is posed in a chemical solution treatment process after via holes are formed.